Top quark
The top quark, also known as the t quark (symbol: t) or truth quark, is the most massive of all observed elementary particles. Like all quarks, the top quark is an elementary fermion with spin-⁄2, and experiences all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. It has an electric charge of +⁄3 e, It has a massive mass of 173.34 ± 0.27 (stat) ± 0.71 (syst)10 GeV/c, which is about the same mass as an atom of tungsten. The antiparticle of the top quark is the top antiquark (symbol: t, sometimes called antitop quark or simply antitop), which differs from it only in that some of its properties have equal magnitude but opposite sign.